$ { \left[\begin{array}{rr}{-1} & {0} \\ {-2} & {0}\end{array}\right]-\left[\begin{array}{rr}{1} & {-1} \\ {-1} & {3}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{-1}-{1} & {0}-{-1} \\ {-2}-{-1} & {0}-{3}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-2} & {1} \\ {-1} & {-3}\end{array}\right]}$